Apparatus and method for supplying gas to a high-temperature process



Oct. 10, 1967 w. E. SHEPHERD APPARATUS AND METHOD FOR SUPPLYING GAS TO A HIGH-TEMPERATURE PROCESS 2 Sheets-Sheet 1 Filed July 23, 1964- FIGZ FIG?) FIG] SUPPORT AND VERTICAL l ADJUSTMENT MEANS INVENTOR.

WTLLIAM E. SHEPHERD A TTORNEYS 0 9 a 6 4 3 I 3 S A G G 5 ms YE LC m P m E m Hw P M EDR H w 8m Em E .WG WA H WA T 0 MT A P P. A

Oct. 10, 1967 Filed July 23, 1964 2 Sheets-Sheet 2 WATER lN Wil Ei----- v 5 I INVENTOR.

WILLIAM E. SHEPHERD WATER OUT ,1 TTOR NE Y5 in E United States Patent 3,346,190 APPARATUS AND METHOD FOR SUPPLYING GAS TO A HIGH-TEMPERATURE PROCESS William E. Shepherd, Alien Park, Micl1., assignor to National Steel Corporation, a corporation of Delaware Filed July 23, 1964, Ser. No. 384,679 1 Claim. (Cl. 239132.3)

This invention relates to refining of metal and more particularly to a novel steelmaking process employing oxygen and to novel apparatus for introducing oxygen into such a process.

It is an object of the present invention to provide a novel process for producing steel with the use of oxygen which results in high production with minimum consumption of oxygen.

Another object is to provide a steelmaking process in which oxygen is jetted downwardly on a bath confined in a refractory lined vessel by means of a lance device, the oxygen being jetted in a novel manner to provide optimum penetration of the bath by the oxygen jet and optimum impingement area between the bath and the oxygen jet.

Another object is to provide a process having the foregoing characteristics which is capable of introducing high rates of oxygen flow into the furnace.

Another object is to provide a process of the foregoing type in which the character of the oxygen jet may be varied during the process to obtain optimum penetration area and jet impact pressure for varying conditions of the process.

Still another object of the present invention is to provide a novel apparatus for jetting oxygen into a high temperature reaction zone such as a converter for holding molten metal in a steelmaking process.

A still further object of the present invention is to provide a novel lance apparatus for jetting gas such as oxygen provided with means for varying the characteristics of the jet without changing the pressure of the gas feeding the apparatus or the position of the apparatus.

Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings which disclose one embodiment of the invention. It is to be expressly understood that the drawings are designed for purposes of illustration only and not as a definition of the limits of the invention, reference for the latter purpose being had to the appended claims.

In the drawings, in which similar reference characters denote similar elements throughout the several views:

FIGURE 1 is a diagrammatic view of a lance apparatus embodying the principles of the present invention illustrated in combination with a basic oxygen furnace for performing the novel steelmaking process provided by the present invention;

FIGURE 2 is a diagrammatic view including the discharge end of the lance apparatus of FIGURE 1 illustrating one mode of operation;

FIGURE 3 is a diagrammatic view including the discharge end of the lance apparatus of FIGURE 1 illustrating another mode of operation;

FIGURES 4A and 4B are views in cross section of the lance apparatus shown in FIGURE 1, FIGURE 4A showing the upper portion of the lance apparatus and FIG- URE 43 showing the lower portion of the lance apparatus; and

FIGURE 5 is a view in plan of the discharge end of the lance apparatus shown in FIGURE 4B.

Apparatus for performing the novel steelmaking process in accordance with the present invention is shown in 3,345,190 Patented Oct. 10, 1967 FIGURE 1 including a novel lance apparatus 19 in combination with a basic oxygen furnace 11. The furnace 11 comprises a vessel made up of an outer steel shell 12 and an inner lining 13 of refractory material and having a converging upper portion 14 providing a restricted opening or nose 15 at its top. The vessel defines a Zone 16 illustrated as containing a bath 17 of molten metal; it is understood of course that, during initial phases of the steelmaking process, the zone may be charged with solid scrap as well as hot metal. The lance apparatus 10 includes a lower large diameter portion 18 having a discharge end 19, a first intermediate portion 20 of less diameter, a second intermediate portion 21 of still less diameter, and an upper end portion 22. The portions 18, 2d and 21 are joined together as an integral structure and the portion 22 is movable relative thereto for a purpose that will be described below. The lance apparatus 10 is mounted with its longitudinal axis substantially coincident with the central vertical axis of the vessel 11 and so that the lance apparatus 10 may be moved vertically with respect to the vessel 11 so as to adjust the position of the discharge end 19 relative to the surface 23 of the bath 17 and also to move the lance apparatus 10 upwardly so that the discharge end 19 is spaced height- Wise with respect to the upper end of the vessel to permit the vessel to be tilted for receiving the charge and for discharging product therefrom. The equipment for movably supporting the lance apparatus 10 in the foregoing manner may be of conventional construction and is diagrammatically shown in the drawing as support and vertical adjustment means 24 joined by bracket 25 to the lance apparatus 10.

As will be described in detail below, the lance apparatus 10 functions to discharge gaseous oxygen from its discharge end 19 downwardly in a direction toward the surface 23 of the bath 17, the oxygen being introduced into the lance apparatus by a conduit 26. The lance apparatus is also provided with means for circulating coolant fluid such as water therethrough and, in its preferred form, two separate cooling circuits are provided. One cooling circuit which meets the primary cooling requirements is located for the most part within the lower portion 18 and includes coolant fluid inlet conduit 27 and coolant fluid outlet conduit 28. The second cooling circuit which functions for the most part to cool a specific element of the lance apparatus located in the region of the discharge end 19 extends substantially throughout the entire length of the lance apparatus 10 with the coolant fluid entering through the portion 22 which, as described below, may be in the form of a conduit, and with the cooling fluid being discharged through conduit 29.

The novel steelmaking process provided by the present invention is an improvement on the basic oxygen furnace process in which oxygen is jetted downwardly onto and into a bath of molten impure iron and scrap contained within a refractory lined vessel such as vessel 11 of FIG- URE l, the oxygen being discharged onto and into the bath by a vertically disposed lance device extending into the vessel through its open top generally in the manner of the lance apparatus 10 of FIGURE 1. While a number of factors influence the production obtainable from a basic oxygen furnace installation, it is known that a high order of production requires producing heats of high quality steel with minimum blowing time; maintaining clean blowing conditions, that is, the blowing of oxygen with minimum splashing and slopping; and, the ability to blow a large number of heats without replacing the refractory lining of the vessel or the lance apparatus. All of the foregoing requirements are influenced in one way or another by the manner in which the oxygen is introduced onto and into the bath. In particular, it has been determined that the oxygen must be jetted onto the surface of the bath so as to impinge a certain area of the bath with sufiicient impact pressure so that the oxygen jet penetrates sufiiciently into the bath to effect adequate circulation of the bath but not to an extend to damage the refractory in the bottom of the vessel while maintaining the discharge end of the lance apparatus spacedproper distances heightwise from the surface of the bath and the nose of the vessel to insure maximum lance life. These requirements become more critical and more difficult to satisfy as the capacity of the vessel increases with concomitant increase in the mass of oxygen introduced into the vessel. This results at least in part by the limitation on the maximum depth of the bath due to scrap melting requirements which results in the area of the bath increasing with relatively small increases in bath depth as the capacity of the vessel is increased. In the past, a lance apparatus including a single orifice located on the longitudinal axis of the apparatus has been employed to introduce oxygen into basic oxygen furnaces. Due to inherent characteristics of single orifice lances and the requirements of the oxygen jet with respect to impact area and impact pressure and the required position of the lance apparatus with respect to the bath and the vessel nose, it has not been possible to obtain optimum production in basic oxygen furnaces using single orifice lances especially in furnaces of high capacity such as 150 tons and greater.

The present invention provides a novel method of introducing oxygen into basic oxygen furnaces which makes it possible to obtain optimum production even with furtraces of high capacity. This is accomplished by novel apparatus which functions to jet the oxygen downwardly onto the bath about a vertical axis passing through the center of the vessel, the oxygen being jetted downwardly from the discharge end of the lance apparatus from regions spaced uniformly above the bath and located about and displaced laterally from the vertical axis with the jetted oxygen following paths which diverge outwardly from the central axis. In accordance with the present invention, the foregoing is accomplished by the provision of a lance apparatus having a discharge end provided with an outwardly inclined annular nozzle so as to produce a conically shaped oxygen jet which is impinged upon the bath centrally of the longitudinal axis of the lance apparatus which preferably is positioned in substantial alignment with the central vertical axis of the vessel. As shown in FIGURE 2, the novel lance apparatus at its discharge end 19 includes an outer structure 30 presenting an internal cylindrical surface 31 and an inner structure 32 presenting an external cylindrical surface 33, the surfaces 31 and 33 being in spaced relationship to define an annular oxygen passageway 34. The outer structure 36 includes an annular end portion 35 presenting an internal circumferential surface 36 inclined outwardly with respect to the longitudinal axis of the lance apparatus while the inner structure 32 includes a center end portion 37 provided with an external circumferential surface 38 likewise inclined outwardly with respect to the longitudinal axis. The circumferential surfaces 36 and 38 coact to define a nozzle 39 of generally annular shape through which the oxygen from the passageway 34 is discharged from the apparatus. It is understood of course that the surfaces as and 38 may be shaped to provide a discharge nozzle of non-annular form. The oxygen jet emerging from the inclined annular nozzle 39 is of generally conical shape and will effect jetting of oxygen downwardly and outwardly from regions spaced from the longitudinal axis of the lance apparatus as indicated by jet patterns 40, 40 which would appear from a vertical section taken through the conically shaped jet. The fea ture of jetting oxygen from regions spaced from the longitudinal axis of the lance apparatus and downwardly toward the bath and outwardly with respect to the longitudinal axis makes it possible to obtain an optimum area of impingement of the jetted oxygen on the surface of the bath with controlled impact pressure to provide optimum penetration with the discharge end of the lance apparatus positioned within permissible limits above the surface of the bath and below the nose of the vessel. This result is of particular importance in connection with furnaces of large capacity which have not been operable up to design production by use of single orifice lance apparatus. \Vhile single orifice lances may be designed to provide high rates of oxygen flow, it is believed the unsuccessful performance with high capacity furnaces results from the high flow producing high impact pressure without substantial increase in the impingement area. The feature of jetting the oxygen from regions spaced from the longitudinal axis of the lance apparatus downwardly toward the bath and outwardly from the longitudinal axis not only makes it possible to obtain an optimum impingement area but reduces problems attendant high impact pressure of a single orifice lance designed for high rates of oxygen flow. 7

The conically shaped oxygen jet impinges upon the surface 23 of the bath in an area of generally annular shape and the jet penetrates into the bath throughout its circumference as indicated when viewed in section by penetration regions 41-41 occurring at diametrically opposite sides of the longitudinal axis. The force of any portion of the jet will be confined circumferentially by the portions of the jet on both of its sides and thus the impact pressure or force of penetration of any increment of the oxygen jet will induce substantially uniform agitation of the bath throughout the circumference of the penetrating jet. Such uniform agitation will induce in turn substantially uniform circulation of the bath throughout a portion of the bath centrally located with respect to the vertical axis of the furnace.

During phases of basic oxygen furnace operations, it is desirable to vary area of impingement of the oxygen jet on the surface of the bath. In the past, this result has been sought by varying the pressure of the oxygen fed to the lance apparatus or by changing the distance between the discharge end of the lance apparatus and the surface of the bath or by a combination of these two variables; however, in view of the requirement to maintain an oxygen jet of adequate impact pressure, the result has been difficult to achieve.

The lance apparatus provided by the present invention include adjustable nozzle means which makes it possible to vary the impact area of the oxygen jet without varying the height of the lance apparatus or the oxygen pressure. As shown in FIGURES 2 and 3 and as described in detail below in connection with FIGURES 4A and 4B, the inner structure 32 is movable axially of the lance apparatus relative to the outer structure 30 to vary the effective size of the nozzle 39 at least with respect to the shape of the oxygen jet. FIGURE 2 illustrates the inner structure 32 in its uppermost position to provide a conical jet of maximum outward flare while, in FIGURE 3, the inner structure 32 is shown in a downward position relative to the outer structure 30 to provide a conical jet of less flare. It will be appreciated adjustment of the inner structure 32 to the positions shown in FIGURES 2 and 3, and any intermediate position, will result in establishing different areas of impingement of the conical jet on the surface of the bath without varying the height of the lance apparatus relative to the bath. It is to be understood that in FIGURES 2 and 3 the distance between the discharge end 19 of the lance apparatus and the surface 23 of the bath is diagrammatic and not an illustration of the heightwise space between the surface of the bath and the lance apparatus in actual operations.

Details of a lance apparatus embodying the features of the present invention is shown in FIGURES 4A, 4B and 5 of the drawings. As shown, the inner cylindrical surface 31 and the outer cylindrical surface 33- defining the walls of the annular space 34 for the flow of oxygen are defined by concentric tubular members 50 and 51, respectively. The tubular member 50 extends from the annular end portion 35 through the portions 18 and 20 and is joined to a hollow cylindrical block 52 to which is connected the gas inlet conduit 26 while the tubular member 51 extends from the end portion 37 throughout the portions 18 and 20 and also through an opening in the block 52 and is secured to an annular sleeve 53. The outer surface of the sleeve 53 is in sliding engagement with a tubular member 54 extending upwardly from block 52 and sealing means such as a plurality of O-rings 55 are provided. The tubular members 50 and 51, together with the annular sleeve 53, provide a closed passageway for the flow of oxygen from the conduit through the passageway 34 and from the circumferential nozzle 39 at the discharge end of the apparatus.

An outer tubular member 56 extends from the annular end portion 35 in concentric spaced relation with the tubular member 50 throughout the portion 18 and terminates in an annular flange 57 defining a chamber 58 in communication with the coolant inlet conduit 27. The annular space between the tubular members 50 and 56 is divided by cylindrical spacer 59 into annular spaces 60 and 61. The upper end of the space 61 is closed between the inlet and outlet conduits 27 and 28 by an annular sleeve 62 and the lower end 63 of the spacer 59 terminates in spaced relationship with the internal wall of the annular end portion 35. The coolant inlet conduit 27 thus communicates with chamber 58 and the annular space 60 and the annular space 61 communicates with the coolant outlet conduit 28. i

A conduit 65, the upper end of which comprises the portion 22 of the apparatus, extends from above and passes through the entire length of the tubular member 51 and terminates at its lower end 66 in spaced relationship with the inside wall surface of the end portion 37. The sleeve 54 is joined at its upper end to an annular sleeve 67 in sealing engagement with the conduit 65, such as by O-rings 68. The sleeve 54 forms a space 68 between the annular sleeves 53 and 67 which communicates with the water discharge outlet 29 and the annular space 69 between the conduit 65 and the tubular member 51 while the conduit 65 functions to introduce coolant to adjacent the end portion 37. The conduit 65 and the tubular member 51 are joined together as a unitary structure by any suitable means such as a series of spacers 71 joined between the conduit 65 and the inner Wall of the tubular member 51 at angularly spaced points so as not to impede the flow of coolant fluid through the intervening space.

The inner structure 32 is movable relative to the outer structure longitudinally of the apparatus to adjust the position of the end portion 37 relative to the annular end portion as described above. The lower end of the tubular member 51 is provided with lateral support to maintain the end portion 37 in alignment with the annular end portion 35 by means of a plurality of radial spacers 75 secured to the outer surface of the tubular member 51 and provided with anti-friction bearings 76 in contact with the inner surface of the tubular member 50. The upper end of the tubular member 51 and the upper end of the conduit 65 are maintained in proper alignment by the annular sleeves 53 and 67, respectively. The end portion 37 is longitudinally moved by imparting upward or downward movement to the conduit 65 such as by means of a rack 77 secured to the conduit and a pinion 78 driven by any suitable controllable means, not shown. As shown in FIGURE 1, the pinion 78 may be supported integrally with the lance apparatus supporting means by a bracket 79.

It will be apparent from the foregoing that upon downward movement of the conduit 65 the tubular member 51 and the center end portion 37 will move therewith thereby adjusting the relative position of the center end portion 37 with respect to the annular end portion 35.

Inasmuch as the center end portion 37 of the discharge nozzle is in close contact with the high temperature bath when in its position as shown in FIGURE 2 but is moved into closer contact with the bath upon adjustment of the nozzle toward the FIGURE 3 position, it is an important feature of the present invention to provide an arrangement for feeding coolant fluid to the center end portion 37 independent of the coolant circuit for the main body of the lance apparatus and irrespective of the position of the center end portion 37 relative to the annular end portion 35. It will be appreciated from the foregoing description that the coolant circuit for the center end portion 37 not only operates independently of the coolant circuit for the portion 18 of the lance apparatus but is so operable at any position of the center end portion 37 throughout its range of adjustment. The member including the center end portion 37 may be threadably joined to the tubular member 51 to readily incorporate in the lance apparatus different sizes or shapes of the nozzle forming surface of the center end portion 37.

In operation, the furnace 11 is charged with scrap and hot metal and the lance apparatus lowered through the opening 15 and with its discharge end 19 within the furnace spaced heightwise above the charge as shown in FIGURE 1. Thereupon oxygen is fed to the lance apparatus and oxygen is jetted onto the charge while slag forming fluxes are introduced into the furnace. During the initial period of the blow when the slag is being formed, the discharge end of the lance apparatus is ordinarily located at a relatively high position to minimize the impact pressure of the oxygen jet and, during this phase of the operation, the center end portion 37 may be adjusted relative to the annular end portion 35 to obtain optimum penetration pressure of the oxygen jet during the slag forming phase. After the slag is formed, the lance apparatus is lowered to an optimum position above the surface of the bath and the oxygen blow is continued until the bath is refined to the desired degree. During the blow, to effect the refining the center end portion 37 may be adjusted to vary the area of impingement and penetration pressure of the oxygen jet to obtain optimum blowing conditions irrespective of variation in the process such as foaming slag and occurrence of slopping conditions, for example.

Although only one embodiment of the various features of the invention has been disclosed and described herein, it is to be expressly understood that various changes and modifications may be made therein without departing from the spirit of the invention as understood by those skilled in the art. For example, the novel method may be used in connection with the refining of metal other than iron and the lance apparatus may be employed in other processes in which a reaction gas is discharged downwardly on a reaction mixture enclosed within a vessel. Reference therefore will be had to the appended claims for a definition of the limits of the invention.

What is claimed is: Apparatus for supplying gas to a region of high temperature comprising an elongated structure having an outer shell and a gas inlet end and a gas discharge end, 7

the elongated structure including passageway forming means located within the outer shell in spaced rela tion therewith and defining a centrally disposed elongated passageway extending between the gas inlet end and the gas discharge end,

annular closure means at the discharge end joined between the outer shell and the passageway forming means for closing the space between the outer shell and the passageway forming means,

the closure means including an internal conical surface forming an extension of the centrally disposed elongated passageway,

the internal conical surface being inclined outwardly relative to the central longitudinal axis of the elongated passageway,

an elongated hollow member centrally disposed within the elongated passageway,

the elongated hollow member having a cross-sectional area less than the cross-sectional area of the elongated passageway to provide an annular space between the passageway forming means and the elongated hollow member,

the elongated hollow member including a terminating closed end portion at the discharge end,

the terminating end portion including an external conical surface inclined outwardly relative to the central longitudinal axis of the elongated passageway,

said internal surface and said external surface being complementary and spaced from each other and together defining an annular discharge nozzle communicating with the annular space,

means at the gas inlet end for feeding gas to the annular space,

means for adjusting the relative positions of the internal and external surfaces along the central longitudinal axis,

the last-named means including means at the gas inlet end for moving the elongated member relative to the passageway forming means between a first position in which said external surface faces said internal surface and a second position in which the external surface is located beyond the closure means,

and means for circulating coolant fluid within the elongated hollow member and into contact with the internal surface of the terminating end portion of the elongated member.

References Cited UNITED STATES PATENTS 2,803,534 8/1957 Cnscoleca et al -60 2,829,960 4/ 1958 Vogt 756O 2,991,173 7/1961 Trentini et a1. 3,130,252 4/ 1964 Metz 266-34 3,194,650 7/1965 Kurzinski 75 43 3,220,716 11/ 1965 Armstrong et al 266-34 3,224,749 12/1965 Berry 26634 FOREIGN PATENTS 216,032 7/ 1961 Austria. 876,687 9/1961 Great Britain.

BENJAMIN HENKIN, Primary Examiner. 

